Show Me Some Science! Beachball Under Pressure

A small hose is filled with a bucket of water, and attached to a beachball, which is lowered off of the 3rd floor balcony. Water continues to fill the ball, leading to explosive results

What’s Going On

We have essentially made a siphon. Water molecules are sticky, and when one falls down the hose due to gravity, other water molecules follow with it. The pressure of the water at the bottom of the hose is greater than at the top, due to the weight of all of the water in the hose.

According to Pascal’s Law, this increase in pressure is the product of the density of the water, the acceleration due to gravity, and the height of the top of the tube:

P= ρgh=(1000 kg/m^3)(9.8m/s^2)(10m).

The pressure at the bottom is nearly 100,000 Pascal (14 psi) higher than the top, plenty to stretch and even pop the beachball!